Error with some italic fonts: Parsing CFF DICT failed

["Robert-André Mauchin" <zebob.m@pengzone.org>]

Hi,

So I finally understand how to use my system fonts with Context (the 
--reload thing was not working), in order to use URW fonts, especially 
Nimbus Roman ones (I know there are TexGyre versions but that's not the 
point).

  * Here is my code :

     % engine=luatex
     \starttypescript [serif] [nimbus] [name]
       \definefontsynonym [Serif]            [n021003l]
       \definefontsynonym [SerifBold]        [n021004l]
       \definefontsynonym [SerifItalic]      [n021023l]
       \definefontsynonym [SerifBoldItalic]  [n021024l]
     \stoptypescript

     \definetypeface[basic][rm][serif][nimbus]
     \setupbodyfont[basic,12pt]

     \starttext
     blah blah blah
     \stoptext

  * When I compile this with Context, I get the following error :

!LuaTeX error (file 
/usr/local/tex/texmf/fonts/data/default/Type1/n021023l.pfb): Parsing CFF 
DICT failed. (error=-3)
  ==> Fatal error occurred, no output PDF file produced!
MTXrun | fatal error, return code: 70

It happens with other italic URW fonts, such as Palladio.


  * Googling a bit the error message, I found a similar error message 
but with Xetex (http://www.tug.org/pipermail/xetex/2008-March/009000.html ):

 >> OK, I think I have figured out what's wrong. The italic version
 >> of the font has an empty StemSnapV array in its PS Private data,
 >> and this stumbles xdvipdfmx which assumes every operator should
 >> be preceded by some operands. Particularly I think this is a bug
 >> in xdvipdfmx: although the specification doesn't say explicitly
 >> that dictionary keys with no value are allowed, other tools
 >> (e. g. TTX or FontForge) seem to have no problems with this
 >> situation.
 >>
 >> So my opinion is that the CFF_ERROR_STACK_UNDERFLOW error should
 >> not be triggered at the line 305 of cff_dict.c, if stack_top is 0.
 >
 > Thanks for your analysis of the issue. You are right, it is unclear
 > from the CFF spec whether an operator like StemSnapV should be
 > allowed with no operands; it doesn't really make any sense, but on
 > the other hand it should be harmless.

  * So I searched in the luatex code to find the culprit, 
source/texk/web2c/luatexdir/font/writecff.c, where you might include a 
similar hack as in xdvipdfmx 
(http://scripts.sil.org/svn-view/xdvipdfmx/TRUNK/src/cff_dict.c?view=markup 
)

Thanks
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